Australian Greens Leader Christine Milne says Tony Abbott has sent Australians to another war in Iraq with a claim that following the United States is in our national interest.

"The Greens stand with those Australians who are asking why is it in Australia's national interest to join in a another war in the Middle East without a clear strategic objective or risk assessment?" Senator Milne said.

"How will this war make us safer? Won't it make us a bigger terrorism target and a more attractive recruiting ground for jihadists?

The Australian Greens accept the advice of ASIO on threats to Australia but say we cannot ignore the impact of military engagement in Iraq and the Middle East in increasing the risk at home. Back in 2004, Federal Police Commissioner Mick Keelty said Australia was at increased risk because of our involvement in the Iraq war, and Greens Leader Christine Milne says the same applies now.

"We cannot bring Australians together and combat extremism at home by blindly following the USA into yet another Iraq war," said Senator Milne.

Greens Leader Christine Milne says Australia is witnessing mission creep in action, as the Foreign Minister says 'no boots on the ground,' but commits to joining an expanded military engagement in Iraq as soon as a formal request is made.

"Julie Bishop has written a blank cheque, telling the US it only needs to say the word and Australia will join in. But join in what?

"How long will military engagement in Iraq go on? What is the objective? Do we have any hope of achieving it?